Plate clamp registering mechanism



Oct. 12, 1955 R. K. NORTON mms CLAMP REGISTEMNG MACHANISM United StatesPatent Office Re. 25,877 Reissuecl Oct. 12, 1965 25,877 PLATE CLAMPREGIS' ERING MECHANISM Robert K. Norton, Twinsburg, Ohio, assignor toHarris- Intertype Corporation, Cleveland, Ohio, a corporation ofDelaware Original No. 3,168,040, dated Feb. 2, 1965, Ser. No. 210,632,July 18, 1962. Application for reissue Mar. 17, 1965, Ser. No. 455,027

12 Claims. (Cl. lOl-415.1)

Matter enclosed in heavy brackets appears in the original patent butforms no part of this reissue specification; matter printed in italicsindicates the additions made by reissue.

This invention relates generally to clamps for iiexible printing plates,and in particular to means for rapidly and accurately registering such aplate clamp in an exact, predetermined position relative to itscylinder, whereby a plate properly registered to the clamp will therebybe properly registered to the cylinder and press.

Various systems have been proposed for registering printing plates toprinting cylinders over the years. Whenever a plate clamp mounted onsuch a cylinder had plate aligning means thereon, it was neverthelessoften found necessary to move the clamp relative to the cylinder oncethe plate had been locked thereto. Even the most perfect pre-registersystems known to date are subject to occasional problems in that humanerror may cause an image to be slightly off with respect to the plate,or improper plate handling during installation on a cylinder may causepoor register. If proper register is not obtained upon installation, itis normal to move the plate clamp to rectify the situation. Movement ofthe plate clamp from its original position when installing the first ofo group of plates naturally requires that the clamp be restored or resetto that position when the iirst printing plate is removed therefrom, inorder that the next plate may be preregistered to the cylinder.

Some proposals for resetting plate clamps were to use screws withmicrometer settings lined up with a pointer, or to use feeler gauges foraligning the plate clamp with the cylinder body after the plate has beenremoved. While these have been effective to a degree, they have certaininherent disadvantages.

A serious disadvantage of micrometer adjusting screws is that wear orrough handling by pressmen would often destroy the accuracy of suchscrews, particularly since their threads must be held to very closetolerances and must be closely tted. Rust, ink and various printingchemicals tend to get on the screw threads and dials and make micrometersettings impractical.

In those instances where attempts were made to restore the plate clampsto an original condition on the cylinder by means of feeler gauges, itwas often found that dirt, ink, corrosion, machining inaccuracies, anddamage to machined surfac-es would prevent accurate re-alignment of theplate clamp with the cylinder after the mechanism had been in useawhile. The use of feeler gauges is subject to a still furtherdisadvantage in that each operator has a different feel, and the settingmay vary from one shift to another. In both of the previously mentionedsystems, the amount of time it took to reset the clamps on the cylinderwas too great to warrant use of such preregistering systems, and as aconsequence, clamp register has been obtained by the trial-and-errormethod.

It is a principal object of this invention to enable quick and accuraterestoration of the relationship of a plate clamp to its plate cylinderafter a flexible printing plate has been removed therefrom.

A more specific object is to enable rapid make-ready through use of aplate pre-registering system employing plate clamps which can be quicklyand accurately prepositioned on a plate cylinder.

Still another object is to make provision for the occasional inadequencyof plate pre-register systems to compensate for unforseen registerproblems caused by human error in the plate making or plate handlingprocess.

Other objects and advantages will be apparent from the followingdescription in which reference is made to the accompanying drawings.

In the drawings:

FlG. 1 is a view of a printing press plate cylinder having plate clampsfor receiving the leading and trailing edges of a flexible printingplate, and

FIG. 2 is an enlarged, cross-sectional fragmentary view of a portion ofthe plate clamp pre-registering means according to the invention, and istaken susbtantially along line 2 2 of FIG. l.

According to the invention, a plate cylinder 10 is mounted for rotationin side frames (not shown), and carries a leading edge plate clamp 12and a plurality of trailing edge plate clamps 13 in a gap 1l. In thatform of the invention illustrated herein, the leading edge plate clamp12 includes an elongated bar 14 which acts as the lower jaw of theclamp, and a plurality of upper jaws 15 which are capable of beingindependently clamped upon a plate 16.

The plate 16 is shown in dot-dash lines in FIG. l as it is initiallyinserted between the jaws 14 and 15 of the plate clamp 12 and registeredagainst a round register pin 17 and one side of a square register pin18. In the form of register system shown herein, it will be seen thatthe pin 17 is encompassed by the plate on one-half of its circumference, thus providing both front and side register of the plate,while the square pin 18 provides front register of the plate only, sincea notch 19 in the register edge of the plate 16 is wider than theportion of the pin 18 engaged thereby. The pins 17 and 18 and theircorresponding notches effectively provide what is commonly referred toas three-point register of the plate 16 to the plate clamp 12. It is tobe understood that the plate 16 was previously prepared as alithographie or relief printing plate of the flexible variety, with theimage portions thereon being in exact registration with the registernotches in the leading edge of the plate. I prefer that the plate beprepared in accordance with the method described in my copending U.S.patent application Ser. No. 660,688, filed May 21, 1957, and nowabandoned. I wish it to be understood, however, that any plateregistering system or plate preparation system may be employed with theinvention described herein.

The plate 16, after being held in position by a prcssman against theregister pins 17 and 18 with jaws 15 open, is clamped to the leadingedge plate clamp l2 by actuating each of the jaws 15 to clamp the plate16 against the bar 14. Jaws 15 are actuated to locked position byrotation of a longitudinally groovcd shaft 2l). (See FIG. 2.). Thegroove of the shaft, when coinciding with the tail 1S' of the jaw 15,enables the jaws to be opened in a clockwise direction by spring means(not shown). The jaws 15 are pivoted about round-headed screws 21 inconventional fashion. When the shaft 20 is actuated to the positionshown in FIG. 2, the clamping edge of the Lipper jaws 15 are cammed topivot counterclockwise about the heads of screws 21 to lock onto andgrip the plate 16.

Once the leading edge of the plate 16 s gripped by the clamp 12, thecylinder is rotated until the plate 16 is wrapped about the cylinderunder pressure from another cylinder. This wrapping takes place untilonly the trailing edge portion of the plate 16 remains free. Thetrailing edge of 'the plate is then tucked into the jaws of the trainingedge plate clamps 13 in similar fashion to the manner in which theleading edge was received by the clamp 12, with the exception that thetrailing edge plate clamps 13 ordinarily will not require the use ofplate preregistering means such as the pins 17 and 18. Each clamp 13includes an upper jaw 22 and a grooved shaft 23. The grooved shafts 20and 23 of the clamps 12 and 13 respectively are actuated by engagingpins in radial holes of enlarged portions 24 of the shafts 20 and 23. Ifeverything in the plate making process has ben performed accurately fromcamera to the press, and if all the registering elements are in theirexact pre-set positions, then the plate 16 should be properly located onthe cylinder 10 when installed, so that the printing job may be runwithout any adjustment of the plate 16 on the cylinder. While this isideal, it is not always possible for this to occur. Any slight error inthe processing or mounting of the plate may cause or require someadjustment of either or both the leading edge clamp 12 or the trailingedge clamps 13 relative to the cylinder. In order to make positivemovements of the plate clamps in tensioning a plate about the cylinder,conventional means such as jackscrews 25 are provided for adjusting theclamps 12 and 13 inwardly of the gap 1l. In addition, jackscrews 26 areprovided for the plate clamps to enable side adjustments thereof.

Pins 27 interconnect the leading and trailing edge plate clamps and thesprings 28 surrounding them between the clamps. The springs 28 urge theclamps 12 and 13 toward the sides of the gap 11 and therefore maintainthe tips of the jackscrews 25 against their respective gap sides.

It will be seen from FIG. 1 that the bar 14 is spaced slightly from theadjacent side or edge 29 of the body of the cylinder 10. This spacingenables the jackscrews 25 to be backed olf to enable the plate clamp 12to be positioned toward the adjacent side 29 a small amount. The presentinvention involves the use of means which predetermines the exactlocation or position of the bar 14 with respect to the adjacent edge 29of the cylinder body. One such pre-positioning means is shown in FIG. 2as being a gauge screw 30 which is threaded into and through the upperpart of the bar 14. The end or tip of the screw 30 forms an abutmentwhich engages the adjacent edge 29 of the cylinder body. It will benoted from FIG. 2 that the screw 30 is slotted as at 31 for purposes tobe described later.

Each gauge screw 30, of which three are shown in FIG. l, has anadjustable nut 32 mounted on one end. The leftward end surface of thatnut forms an abutment which has a definite relationship to the abuttingtip of screw 30. as will be seen. The nut 32 is threaded radially toreceive a set screw 33 which is capable of locking the nut relative tothe gauge screw 30. As shown in FIG. 2, a spacer 34 may be employed tosurround a portion of the gauge screw 30. Actually, the spacer is usedin the illustrated design merely because space limitations between thegauge screw 30 and the shaft 20 do not permit the nut 32 to reach beyondthe shaft 20 to the bar 14 without sacrificing strength of the parts.The spacer 34 is tlattened on the side next to the shaft 20 and has anopening therethrough permitting free passage of the screw 30. Each nut32 is provided with radial pin-receiving holes to receive a tool, thusenabling the screws 30 to be backed olf when the bar 14 is to be movedtoward the adjacent edge of the cylinder body. This enables the springs28 to urge the plate clamp 12 leftwardly as shown in FIG. 2. Theleftward movement is permitted by the space between the bar 14 and theadjacent edge 29 of the cylinder body. The abutting tips of the screws30 would tend to separate from the edge 29, but the springs 2S move thebar 14 leftwardly, instead.

Both ends of the spacer 34 and the portion of the bar 14 engaged by thespacer 34 are provided with accurate bearing surfaces. The abutment onthe nut 32 is engageable with the right bearing surface of the spacer34. This enables the nut 32 to be relatively tightened against thespacer 34 (and thus bar 14), to predetermine the amount that theabutting tip of the gauge screw 30 extends beyond the side of the bar 14facing the adjacent edge 29 of the cylinder body. In this fashion, cachgauge screw acts similarly to a feeler gauge, with the main differencebeing that the abjustment feel will always be almost identical, sincethe gauge screws 30 merely need be tightened to position. Once a gaugescrew 30 is locked in abutmentengaging position as shown in FIG. 2,there need be no further adjustment, as is commonly required when usingfeeler gauges or micrometer gauge screws which align with micrometermarkings on the cylinder or other member.

lt will be seen that any slight inaccuracy in the machining of the edge29 of the cylinder, or in the threads of the gauge screws 30 or the bar14 can be compensated for very easily by merely loosening the set screw33, repositioning the nut 32 relative to the gauge screw 30 by means ofslot 31 and the radial holes in the nut, and again locking the set screw33. The gauge screw nuts 32 may be factory-set and not tampered with fora long period. If any wear of the parts should occur, the nut 32 may bereset for another long period.

With the plate 16 installed in the clamps 12 and 13 of the cylinder 10,and with some minor inward adjustment of bar 14 being required in theevent slight inaccuracies have occurred. the bar 14 may be moved Vawayfrom the edge 29 by merely operating the various jackscrews 25 of bothclamps in conventional fashion. It will be seen that the abutting tipsof the gauge screws 30 will therefore move out of engagement with theadjacent side 29. When the plate 16 is removed and a subsequent printingjob is to be run, the plate clamp 12 should first be restored to itsoriginal position. with respect to the cylinder to enable full advantageto be taken tof the plate pre-registering system provided by the pins 17and 18 and their corresponding notches in the plates. This isaccomplished by merely backing oil the previously adjusted jackscrews25, whereupon the spring 28 surrounding the pins 27 will urged the plateclamp 12 back toward its position until the tip-s of the gauge screws 30abut the adjacent edge 29 of the cylinder body.

Let us assume, however, that when the plate 16 was first installed, ithas to be moved in a direction toward the adjacent edge 29, or aroundthe cylinder toward the trailing edge plate clamps 13. In this case,both the gauge screws 30 and the jackscrews 25 of clamp 12 would firsthave to be backed olf until the springs 28 urged the bar 14 toward edge29 to its proper register position. In this condition the abutting tipsof the gauge screws 30 could provide the positive location of the bar 14relative to the edge 29. Or, if desired, the jackscrews 25 could be usedfor this purpose, or both the jackscrews and gauge screws could be used.Screws 25 of clamp 13 would then be operated to urge the trailing edgeof the plate inwardly of the gap. In this latter example, after a platehas been removed and the plate clamp 12 is to be restored to itsoriginal condition, each gauge screw 30 should be turned until theabutment on its nut 32 engages the bearing surface of the spacer 34 tocause it to bear snugly against its bearing surface formed on the bar14. Once the gauge screw 30 is tight in the bar 14, i.e., with therebeing no space between the abutting and bearing surfaces of the nut 32,spacer 34 and bar 14, the tips of the screws 30 will protrude beyond thebar 14 to the same extent as previously, and the plate clamp 12 willhave been restored to its predetermined original position.

It is obvious that whenever either of the side jackscrews 26 areoperated to effect a side adjustment of the plate clamps 12 or 13, theymust be restored also to position the pins 17 and 18 in their properlocations. Slight corrective measures are normally not required for sideregister in the system described.

Various modifications may be made in the details of construction withoutdeparting from the spirit and scope of the claims.

Having described my invention, I claim:

1. In a rotatable printing press cylinder having a body member and alongitudinal gap in the periphery thereof,

(a) a plate clamp member mounted in and extending along one side of saidgap and adapted to be adjusted generally laterally in oppositedirections from a predetermined plate-receiving position spaced fromsaid gap side,

(b) first means for positively adjusting said clamp member away fromsaid gap side,

(c) second means for moving said clamp member toward said gap side,

(d) plate registering elements mounted on said clamp member forregistering an image-carrying flexible printing plate to said cylinderwhen said clamp member is located in said predetermined plate-receivingposition,

(e) a plurality of spaced gauging elements mounted on one of saidmembers and each having a first abutment engageable with said bodymember and a second abutment engageable with said clamp member, saidabutments, when engaged, serving to positively predetermine theplate-receiving position of the clamp member with respect to said gapside, and,

(f) means for operating each gauging element in a manner normallytending to simultaneously disengage said abutments from said clamp andbody members for enabling said second means to move said clamp membertoward said gap side from its plate-receiving position, said gaugingelements being constructed and arranged to restore said clamp member toits predetermined plate-receiving position upon re-engagement of saidabutments.

2. The invention set forth in claim 1 wherein at least one of saidabutments on each gauging element is adjustable relative to the othersaid abutment, and means for locking said adjustable abutment to itsgauging element.

3. The invention set forth in claim 1 wherein each of said gaugingelements comprises a gauge screw threaded through a portion of saidclamp member and having a tip forming said first abutment engageablewith said body member, a nut adjustably threaded on said screw andhaving a surface forming said second abutment engageable with said clampmember, and means for locking said nut relative to said screw.

4. The invention set forth in claim 3 including means on each gaugescrew providing a tool-receiving portion for enabling operation of eachscrew independently of its nut.

5. The invention set forth in claim 1 wherein said first means foradjusting said clamp member comprises a plurality of spaced jackscrews,and wherein said second means for moving said clamp member comprisesspring means biasing the clamp member toward said gap side.

6. In a rotatable printing press cylinder having a body member andlongitudinal gap in the periphery thereof,

(a) a plate clamp member mounted in and extending along one side of saidgap and adapted to be adjusted laterally in opposite directions from apredetermined plate-receiving position spaced from said gap side, saidclamp member including a bar and a movable jaw mounted on said bar forclamping an image-carrying flexible printing plate between said jaw andbar,

(b) first means for positively moving said bar away from said gap side,

(c) second means for moving said bar toward said gap side,

(d) plate registering elements mounted on said bar for registering theprinting plate and the image thereon to said cylinder when said bar islocated in said predetermined plate-receiving position,

(e) means for operating said jaw to clamp the plate against said bar,

(f) a plurality of spacer gauging elements mounted on one of saidmembers and each having a rst abutment engageable with said body memberand a second abutment engageable with said bar, said abutments, whenengaged, serving to positively predetermine the plate-receiving positionof the bar with respect to said gap side, and,

(g) means for operating each gauging element in a manner normallytending to simultaneously disengage said abutments from said bar andsaid body member for enabling said second means to move said bar towardsaid gap side from its plate-receiving position said gauging elementsbeing constructed and arranged to restore said clamp member to itpredetermined plate-receiving position upon re-engagement of saidabutments.

7. The invention set forth in claim 6 wherein said first means includesa plurality of spaced jackscrews, and wherein said second means includesa plurality of spaced springs biasing said bar toward the gap side.

8. The invention set forth in claim 6 wherein at least one of saidabutments on each gauging element is adjustable relative to the othersaid abutment, and means for locking said adjustable abutment to itsgauging element.

9, The invention set forth in claim 6 wherein each of said gaugingelements includes a screw threaded through said bar and having a tipforming said first abutment engageable with said body member and a nutthreaded on said screw and having a surface forming said second abutmentengageable with said bar, said nut being adjustable along said screw,and means for locking said nut in adjusted position on said screw.

10. The invention set forth in claim 9 wherein the means for operatingeach gauging element comprises tool-receiving portions on each nut foroperating each nut and screw jointly relative to the bar when the nut islocked to the screw.

1l. ln a rotatable plate carrying cylinder ltaving a body member and alongitudinal gap in the periphery thereof,

(a) a plate clump member mounted in and extending along one side of saidgap and adapted to be adjusted generally laterally in oppositedirections from a predetermined plate-receiving position spaced fromsaid gap side,

(b) first means for positively adjusting said clamp member away fromsaid gap side,

(c) second means for moving said clamp member toward said gap side,

(d) plate registering elements mounted on said clamp member forregistering a flexible plate to said cylinder when said clamp member islocated in said predetermined plate-receiving position,

(e) a plurality of spaced gauging elements mounted on one of saidmembers and eaclz having a firs! abn!- ment engageable with said bodymember and a second abutment engageable with said clamp member, saidabutments, when engaged, serving to positively predetermine tlieplate-receiving position of the clamp member with respect to said gapside, and

(f) means for operating eac/i gauging element in a manner normallytending to simultaneously disengage said abutments from said clump andbody members for enabling said second means to move said clamp membertoward said gap side from its plate-recei ving position, said gaugingelements being constructed and arranged to restore said Clamp member toits predetermined plate-receiving position upon reengagement of saidabutments.

I2, In a rotatable plate carrying cylinder having a body member andlongitudinal gap in the periphery thereof,

(ci) a plate clump member mounted in and extending along one side ofsaid gap and adapted to bc adjusted laterally in opposite directionsfrom a predetermined plaie-receiving position spaced from said gap side,said clamp member including a bur and a movable jaw mounted on said barfor clamping a exible plate between said jaw and bar,

(b) first means for positively moving said bar away from said gap side,

(c) second means for moving said bar toward said gap side,

(d) plate registering elements mounted on said bar for registering theplate and thereby predetermined areas thereon to said cylinder when saidbar is located in said predetermined plate-receiving position,

(e) means for operating said jaw to clamp the plate against said bar,

(j) a plurality of spacer gauging elements mounted on one of saidmembers and each having a rst abutment engageable with said body memberand a second abutment engageable with said bar, said abutments, whenengaged, serving to positively predetermine the plate-receiving positionof the bar with respect to said gap side, and,

(g) means for operating each gauging element in a manner normallytending to simultaneously dsengage 15 said abutments from said bar andsaid body member for enabling said second means to move said bar towardsaid gap side from its plateJeceivi/lg position, said gauging elementsbeing constructed and arranged to restore said clamp member to itspredetermined plate-reeeiving position upon re-engagement of saidabutments.

References Cited by the Examiner The following references, cited by theExaminer, are of record in the patented le of this patent or theoriginal 10 patent.

UNITED STATES PATENTS 1,391,l1'l 9/21 Huebner lOl-415.1 2,386,214 10/45Harrold lOl-415.1

2,621,592 12/52 Faeber lOl-47,6

ROBERT E. PULFREY, Primary Examiner.

